A102 INTERDISCIPLINARY TELEHEALTH REFERRAL PATHWAY AND CONSULTATIONS TO IMPROVE OUTCOMES AMONG CANADIAN OLDER ADULTS WITH LIVER CIRRHOSIS

Background

Telehealth and telemedicine have become indispensable healthcare delivery tools during the COVID-19 pandemic. Older individuals with cirrhosis have complex medical needs that are currently unmet due to the growing disease burden and decreased access to care. Delivering timely specialist care virtually to older adults with cirrhosis will likely be beneficial and acceptable to such patients; however, this has not yet been prospectively evaluated.

Purpose

The primary goal is to pilot the delivery of dual specialist care from a hepatologist and geriatrician, delivered virtually, for older adults living with liver cirrhosis who are at high risk of geriatric syndromes (age >/= 65 with frailty, undifferentiated cognitive impairment from dementia or hepatic encephalopathy, recurrent falls, risk factors for polypharmacy and moderate to severe malnutrition). Care is delivered using a dedicated hepatology-geriatric referral pathway. Primary objectives include evaluating the impact of this approach on emergency care and inpatient utilization, along with patient attitude and satisfaction to the virtual interdisciplinary care delivery model.

Method

This pilot quality improvement study was conducted in Halifax, Nova Scotia. Ethics approval was obtained from the Nova Scotia Health Research Ethics Board and the University of Alberta Research Ethics Board. Fifty to one hundred participants (age 65 years or older with at least one geriatric syndrome; diagnosis of liver cirrhosis by liver elastography or liver biopsy, or Fibrosis-4 Index for Liver Fibrosis greater than three and having radiological features of cirrhosis and/or portal hypertension) were recruited between September 2022 to December 2022 at the time of their hepatology consultation. After consent and screening, each patient underwent a telehealth appointment by zoom with a geriatrician within four weeks of their initial hepatology assessment. Follow-up by telephone using a standardized survey regarding ease of access and quality of their telehealth experience then occurred at 3-4 weeks, 3 months and 6 months for emergency room visits and hospital admission status.

Result(s)

Pending

Conclusion(s)

Pending

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Other

Please indicate your source of funding;

Pfizer Canada

Disclosure of Interest

J. Zhu Grant / Research support from: Pfizer Canada, F. Carr Grant / Research support from: Pfizer Canada, P. Tian: None Declared, M. McLeod: None Declared, M. MacFarlane: None Declared, S. De Coutere: None Declared, M. Sun: None Declared, K. Peltekian: None Declared

A208 ASSESSING FEASIBILITY AND ACCEPTABILITY OF AN ONLINE MIND-BODY WELLNESS PROGRAM FOR PRIMARY BILIARY CHOLANGITIS

Background

Persons with primary biliary cholangitis (PBC) experience significantly higher rates of fatigue, stress, anxiety, depression, and impaired health related quality of life (HRQOL) as compared to the general population. While online wellness programming has been shown to be effective in decreasing fatigue and improving mental wellness in a variety of chronic disease populations, limited data is available for PBC.

Aims

This pilot study aimed to assess the hypothesis that a 12-week, online, mind-body wellness program would be feasible (assessed through adherence and retention) and acceptable in people with PBC. We also aimed to explore indicators of impact on measures of wellbeing.

Methods

Persons with PBC were recruited across Alberta and British Columbia in January 2021. The program included a 20–30 minute video containing low intensity mindful movement, meditation, and breathwork (goal 2–3 times/week) as well as a weekly behaviour change tip, PBC tip from a physician, and PBC nutrition tip. The online programming was accompanied by brief (10-minute) once weekly phone check-ins from a member of the study team, and optional once monthly zoom group sessions hosted by the Canadian PBC Society. Satisfaction and adherence were assessed at the end of the study using a survey. The pre-post exploratory efficacy assessment included: fatigue (Modified Fatigue Impact Scale), perceived stress (Perceived Stress Scale), anxiety and depression (Hospital Anxiety and Depression Scale), and HRQOL (PBC-40). Using a qualitative descriptive approach, we conducted semi-structured interviews at the end of the study to explore experiences with the intervention, and gather feedback for improvement.

Results

Participants (N = 32) completed baseline surveys and 29 (91%) were retained to end-of-study. Twenty-five (86%) adhered to the program goal of carrying out the mind-body practice at least 2–3 days per week. Comparing baseline to end-of-study, significant reductions were observed in fatigue (13%, p=0.004), anxiety (30%, p=0.005), and depression (28%, p=0.022), and significant improvements were observed in the PBC-40 itch (22%, 0.043), fatigue (13%, 0.005), cognitive (17%, 0.006), and emotional (18%, 0.001) domains. Eleven individuals participated in qualitative interviews, reporting an increase in energy, a more positive outlook, and increased knowledge of PBC. Feedback supported acceptability (satisfaction score of 90%), with fatigue cited as the primary barrier to increased program participation.

Conclusions

These findings suggest that a 12-week online mind-body intervention is feasible and acceptable to persons with PBC and has promising impact on efficacy. Recognizing the limitations of a single-arm study with a small sample size, a future RCT will be designed using this feedback.

Funding Agencies

MITACS Accelerate, Canadian PBC Society

Optimising antimicrobial use in humans - review of current evidence and an interdisciplinary consensus on key priorities for research

Addressing the silent pandemic of antimicrobial resistance (AMR) is a focus of the 2021 G7 meeting. A major driver of AMR and poor clinical outcomes is suboptimal antimicrobial use. Current research in AMR is inequitably focused on new drug development. To achieve antimicrobial security we need to balance AMR research efforts between development of new agents and strategies to preserve the efficacy and maximise effectiveness of existing agents. Combining a review of current evidence and multistage engagement with diverse international stakeholders (including those in healthcare, public health, research, patient advocacy and policy) we identified research priorities for optimising antimicrobial use in humans across four broad themes: policy and strategic planning; medicines management and prescribing systems; technology to optimise prescribing; and context, culture and behaviours. Sustainable progress depends on: developing economic and contextually appropriate interventions; facilitating better use of data and prescribing systems across healthcare settings; supporting appropriate and scalable technological innovation. Implementing this strategy for AMR research on the optimisation of antimicrobial use in humans could contribute to equitable global health security.

Designing a continuous data-driven feedback and learning initiative to improve electronic prescribing: an interdisciplinary quality improvement study

Introduction

The WHO Global Patient Safety Challenge aims to reduce severe avoidable medication-related harm by 50% by 2023[1]. Research suggests that providing timely, trusted feedback that incorporates relevant action can improve practice. However, a key barrier is lack of prescribing error data. Hospital electronic prescribing (EP) data may help address this gap.

Aims

To explore approaches for continuously monitoring medication safety signals using existing or new EP data, and to deliver personalised prescribing feedback and learning to improve patient safety.

Methods

We conducted a feasibility study (November 2019 - February 2020) on a 28-bed adult gastroenterology. This ward was chosen because of a high prescribing error rate. All foundation year 1 and 2 doctors, and pharmacists on the ward, participated in the study. The study team comprised pharmacists, doctors, quality improvement experts and clinical analysts, and used a quality improvement approach to design and test (i) methods for extracting electronic data to calculate prescribing accuracy rates, (ii) ways to refine a paper-prototype of an electronic pharmacists’ interventions form, (iii) potential digital medication safety indicators, and (iv) approaches for feedback for doctors to augment existing verbal feedback from pharmacists. Data were documented in accordance with local information governance and analysed using Excel. Acceptability and usability was assessed through verbal feedback from participants during weekly huddles. Outcome measures: feasibility of using EP to determine prescribing accuracy, user acceptability and usability of data collection, feedback and learning by pharmacists and doctors. We also measured changes in prescribing accuracy rate, pharmacists’ interventions, and quality of prescribing for targeted problematic medications.

Results

Extracting EP data required multiple data linkages to be configured and validated, and not all required data were available. Potential digital medication safety indicators: utility of the reason code ‘prescribed in error’ and actions by pharmacists to modify medications were limited by underuse and lack of data granularity. After testing different ways to extract relevant EP data, we eventually used a combination of EP and manual retrospective review of electronic patient records to determine prescribing accuracy rates. An intervention form was redesigned to tally interventions and capture details for contextual learning for email feedback to doctors and weekly prescribing improvement huddles. Doctors reported emails as timely and helpful for gaining new prescribing- and system-related knowledge. Pharmacists reported intervention data as providing invaluable evidence to drive improvement.

Statistical process control charts showed no special cause variation around a mean prescription accuracy rate of 98% for inpatient orders, and 87% for discharge orders. By contrast, pharmacists recorded a mean of 10 interventions/day with 7 special cause variation (above upper control limit of 19) in the first two months. Omission of venous thromboembolism prophylaxis was identified as a priority medication issue. Specific prescriber- and system-based improvements were suggested (Jan 2020), some implemented (Feb 2020) and others fed back to the thrombosis committee (Feb 2020).

Conclusion

Harnessing the potential of EP data to improve medication safety requires the workforce to have a deeper understanding of the EP data structure and processes. Using a quality improvement approach, we developed a feedback and learning model that is acceptable and useful to pharmacists and doctors. Further research should explore adapting the approach to other clinical areas.

Reference

1. Sheikh, A., Dhingra-Kumar, N., Kelley, E., Kieny, M. and Donaldson, L. The Third Global Patient Safety Challenge: Tackling Medication-Related Harm. Bulletin of the World Health Organization. World Health Organisation. 2017;95:546-546A.

Branched chain amino acids and carbohydrate restriction exacerbate ketogenesis and hepatic mitochondrial oxidative dysfunction during NAFLD

Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic "ketogenic environment," the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.

Microscopic alterations of vaginal tissue in women with pelvic organ prolapse

The aim of this study was to identify any histological changes between the prolapsed and non-prolapsed vaginal skin to enable us to answer the broader question of whether to excise or re-suture the prolapsed tissue during vaginal reconstructive surgery. Two tissue samples were taken from 20 women who underwent prolapse surgery, one prolapsed and another non-prolapsed tissue. The samples were analysed blind histologically by a pathologist. Our study showed statistically significant differences in three tissue components namely myofibroblast differentiation (0.047), elastin (0.048) and collagen (0.095), depending on whether the tissue was prolapsed or non-prolapsed. However, the study had certain limitations and practical difficulties faced in histological approach of tissue analysis. Histology alone is an insufficient indicator to answer our question and definitive understanding of the prolapsed tissue may result from a randomised study on a larger study population.

Subgroup analysis of efficacy and safety analysis of a randomized, double-blinded controlled phase II study of STA-4783 in combination with paclitaxel in patients with metastatic melanoma

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Background: STA-4783 (S), an inducer of heat shock protein 70 (hsp70) is a bis-thiobenzoylhydrazide compound. S leads to up-regulation of hsp70 in tumor cell lines. Xenograft models of solid tumors showed synergistic anti-tumor activity in combination with paclitaxel (P). The combination P + S, in phase I and II studies, showed dose-related hsp70 induction (evidence of biological activity) and tolerability. Methods: Eligibility was based on a diagnosis of metastatic cutaneous melanoma, ECOG <=2, and prior treatment with 1 or no chemotherapy regimens. A total of 81 patients (pts) were randomized 2:1 (P 80 mg/m2 + S 213 mg/m2:P 80 mg/m2) 3 weeks out of 4 at 21 US clinical sites. The primary endpoint was progression free survival (PFS); secondary endpoints were response rate (RR), and adverse events (AEs). Results: Based on intent-to-treat analysis, the median PFS was 3.68 months (m) for P + S vs. 1.84 m in the P only arm (p=.035). RR was 15.1% in the P + S arm and 3.6% in the P arm. Subgroup analysis showed chemo- naive pts (n=23) with P + S showed a median PFS of 8.28 m vs. 2.40 in the P arm (n=9). For pts with 1 prior chemotherapy, (n=29), PFS on P + S was 3.12 m vs. 1.77 m on P (n=19). Of 19 pts who crossed over at progression, data are available for 14. PFS ranged from 0.72 to 5.5 m. Three of the 14 evaluable pts treated with P alone had rapid progression (0.95, 1.6, and 1.7 m) then significant inversion of the time to progression with the addition of S to P (2.3, 5.5, and 4.2 m) suggesting study drug effect. Scans were done at identical intervals (8 weeks). The proportion of pts with AEs of grade 3 or higher was 54% (n=52) in the P + S group and 57% in the P group (n=28); pts on P received a median of 2 cycles, while pts in the P + S group received a median of 4. Adverse events leading to discontinuation were low in both groups: 10% for the P + S, and 14% for P. Conclusions: The addition of S to P showed an increase in PFS vs. P alone particularly in chemo-naïve pts. A few pts failing single agent P appeared to benefit from P + S. Despite the additional treatment duration in the P + S group the drugs were well- tolerated, and showed mainly P related adverse events. A phase III study is planned to confirm a role for P + S in metastatic melanoma.

[Table: see text]

Transplantation of bioreactor-produced neural stem cells into the rodent brain

The development of new cell replacement strategies using neural stem cells (NSC) may provide an alternative and unlimited cell source for clinical neural transplantation in neurodegenerative diseases such as Parkinson's and Huntington's disease. The clinical application of neural transplantation using NSC will therefore depend upon the availability of clinical grade NSC that are generated in unlimited quantities in a standardized manner. In order to investigate the utility of NSC in clinical neural transplantation, undifferentiated murine NSC were first expanded for an extended period of time in suspension bioreactors containing a serum-free medium. Following expansion in suspension bioreactors, NSC were still able to differentiate in vitro into both astrocytes and neurons after exposure to brain-derived neurotrophic factor (BDNF), suggesting that bioreactor expansion does not alter cell lineage potentiality. Undifferentiated bioreactor-expanded NSC were then transplanted into the rodent striatum. Immunohistochemical examination revealed undifferentiated bioreactor-expanded NSC survived transplantation for up to 8 weeks and expressed the astrocytic immunohistochemical marker glial fibrillary acidic protein (GFAP), suggesting that the host striatal environment influences NSC cell fate upon transplantation. Moreover, no tumor formation was observed within the graft site, indicating that NSC expanded in suspension bioreactors for an extended period of time are a safe source of tissue for transplantation. Future studies should focus on predifferentiating NSC towards specific neuronal phenotypes prior to transplantation in order to restore behavioral function in rodent models of neurodegenerative disease.

Erythropoietin and GDNF enhance ventral mesencephalic fiber outgrowth and capillary proliferation following neural transplantation in a rodent model of Parkinson's disease

Low dopaminergic cell survival and suboptimal fiber reinnervation are likely major contributing factors for the limited benefits of neural transplantation in Parkinson's disease (PD) patients. Glial cell lined-derived neurotrophic factor (GDNF) has been shown to enhance dopaminergic cell survival and fiber outgrowth of the graft site as well as promote behavioral recovery in rodent models of PD, while erythropoietin (EPO) can produce dopaminergic neuroprotective effects against 6-hydroxydopamine (6-OHDA) exposure on cultured neurons and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice. The aim of this study was to determine if fetal ventral mesencephalic (FVM) tissue exposed to hibernation media containing a combination of GDNF and EPO could enhance dopaminergic graft survival, striatal reinnervation and functional recovery in a 6-OHDA rodent model of PD. FVM tissue was dissected from 14-day-old rat fetuses and placed for 6 days in hibernation media alone, and in hibernation media that received either a daily administration of GDNF, EPO or a combination of GDNF and EPO. Following hibernation, FVM cells were transplanted as a single cell suspension into the striatum of unilateral 6-OHDA-lesioned rats. Rotational behavioral assessment revealed animals that received FVM tissue exposed to GDNF, EPO or the combination of both drugs had accelerated functional recovery. Immunohistochemical and stereological assessment revealed a significant increase in graft fiber density and angiogenesis into the graft when compared with control. These findings suggest that the hibernation of FVM tissue in a combination of GDNF and EPO can enhance graft efficacy and may have important implications for tissue preparation protocols for clinical neural transplantation in PD.

Chromoendoscopic surveillance in hereditary diffuse gastric cancer: an alternative to prophylactic gastrectomy?

BACKGROUND

Hereditary diffuse gastric cancer (HDGC) is defined by germline mutations in the E-cadherin gene, CDH-1. The first family in which CDH-1 mutations were identified was a large Maori kindred, where lifetime penetrance is 70%. Prophylactic gastrectomy is an unacceptable option for many mutation carriers. The results of annual chromoendoscopic surveillance using the methylene blue/congo red technique in 33 mutation carriers over a five year period are described.

PATIENTS AND METHODS

Thirty three confirmed CDH-1 mutation carriers (18 males, 15 females), median age 32 years (range 14-69), were enrolled in 1999-2003. Medical records, endoscopy, and pathology were reviewed retrospectively.

RESULTS

Over five years, 99 surveillance endoscopies were performed, of which 93 were chromo-dye enhanced. Sixty nine chromoendoscopies were normal. In 24 procedures, 1-6 pale areas/stomach (size 2-10 mm) were detected post chromo-dye application (totalling 56 pale lesions). One biopsy was taken from each pale lesion: 23 lesions (41%) showed signet ring cell carcinoma (10 patients), 10 lesions (18%) gastritis (four patients), and 23 (41%) normal mucosa (10 patients). No chromo-dyes were used in six procedures with macroscopic lesions (two HDGC, four ulceration). Total gastrectomies from patients with carcinoma were macroscopically normal but pathological mapping showed multiple microscopic foci of early signet ring cell carcinoma. Correlation of chromoendoscopic and gastrectomy findings showed that congo red/methylene blue detected carcinoma foci 4-10 mm in size but not foci <4 mm.

CONCLUSIONS

The use of chromoendoscopy following normal white light gastroscopy facilitated detection of early gastric carcinoma foci not visible with white light gastroscopy. If these findings are validated in other HDGC kindred, chromogastroscopy represents an improved surveillance technique that can be safely considered alongside prophylactic gastrectomy.

Land application of domestic effluent onto four soil types: plant uptake and nutrient leaching

Land application has become a widely applied method for treating wastewater. However, it is not always clear which soil-plant systems should be used, or why. The objectives of our study were to determine if four contrasting soils, from which the pasture is regularly cut and removed, varied in their ability to assimilate nutrients from secondary-treated domestic effluent under high hydraulic loadings, in comparison with unirrigated, fertilized pasture. Grassed intact soil cores (500 mm in diameter by 700 mm in depth) were irrigated (50 mm wk(-1)) with secondary-treated domestic effluent for two years. Soils included a well-drained Allophanic Soil (Typic Hapludand), a poorly drained Gley Soil (Typic Endoaquept), a well-drained Pumice Soil formed from rhyolitic tephra (Typic Udivitrand), and a well-drained Recent Soil formed in a sand dune (Typic Udipsamment). Effluent-irrigated soils received between 746 and 815 kg N ha(-1) and 283 and 331 kg P ha(-1) over two years of irrigation, and unirrigated treatments received 200 kg N ha(-1) and 100 kg P ha(-1) of dissolved inorganic fertilizer over the same period. Applying effluent significantly increased plant uptake of N and P from all soil types. For the effluent-irrigated soils plant N uptake ranged from 186 to 437 kg N ha(-1) yr(-1), while plant P uptake ranged from 40 to 88 kg P ha(-1) yr(-1) for the effluent-irrigated soils. Applying effluent significantly increased N leaching losses from Gley and Recent Soils, and after two years ranged from 17 to 184 kg N ha(-1) depending on soil type. Effluent irrigation only increased P leaching from the Gley Soil. All P leaching losses were less than 49 kg P ha(-1) after two years. The N and P leached from effluent treatments were mainly in organic form (69-87% organic N and 35-65% unreactive P). Greater N and P leaching losses from the irrigated Gley Soil were attributed to preferential flow that reduced contact between the effluent and the soil matrix. Increased N leaching from the Recent Soil was the result of increased leaching of native soil organic N due to the higher hydraulic loading from the effluent irrigation.

Decreased muscarinic1 receptors in the dorsolateral prefrontal cortex of subjects with schizophrenia

To test the hypothesis that muscarinic receptors are involved in the pathology of schizophrenia, we measured muscarinic(1) (M1R) and muscarinic(4)(M4R) protein and mRNA as well as [(3)H]pirenzepine binding in Brodmann's areas (BA) 9 and 40 obtained postmortem from 20 schizophrenic and 20 age/sex-matched control subjects. There was a significant decrease in [(3)H]pirenzepine binding to BA 9 (mean +/- SEM: 151 +/- 15 vs 195 +/- 10 fmol mg(-1) ETE; P< 0.02), but not BA 40 (143 +/- 13 vs 166 +/- 11 fmol mg(-1) ETE), from subjects with schizophrenia. The level of M1R protein (0.11 +/- 0.007 vs 0.15 +/- 0.008 OD; P < 0.01), but not M4R protein, was decreased in BA9 from schizophrenic subjects with neither receptor protein being altered in BA 40. The level of M1R mRNA was decreased in BA 9 (30 +/- 7.0 vs 79 +/- 14 dpm x 10(3) mg(-1) ETE, P < 0.01) and BA 40 (28 +/- 5.9 vs 99 +/- 14, P < 0.01) with schizophrenia but M4R mRNA was only decreased in BA 40 (48 +/- 6.6 vs 89 +/- 9.9, P < 0.005). These data suggest that the M1R, at least in the dorsolateral prefrontal cortex, may have a role in the pathology of schizophrenia.

Viral and chemical tracer movement through contrasting soils

Land treatment of animal or human waste can result in chemical and microbial contamination of shallow ground water and/or water-ways. We investigated the fate of a host-specific Salmonella bacteriophage and a nonreactive chemical (Br-) tracer when applied to large intact lysimeter soil cores (500 mm diam. by 700 mm high). The soils included a poorly drained Gley Soil and well-drained Pumice, Allophanic, and Recent Soils. A depth of 30 mm of water containing the bacteriophage and Br- was applied to the soil at a rate of 5 mm h(-1) followed by up to about 1.8 pore volumes of simulated rainfall. Resulting leachates, collected continuously over at least one pore volume were analyzed for the bacteriophage and bromide (Br-) tracers. Bromide moved uniformly through the Pumice and Allophanic Soils with peak concentrations at about 1 pore volume, while the bacteriophage was detected only at trace levels or not at all. In contrast, both Br- and bacteriophage tracers moved rapidly through Gley and Recent Soils, appearing early in the leachate and then tailing off. Such flow patterns in the Gley and Recent Soils are indicative of bypass flow. Coarse soil structure in the Gley Soil, and finger-flow due to water repellency in the sandy Recent Soil are considered responsible for the observed bypass flow in these two soils. Allophanic and Pumice Soils have finer, more porous soil structure leading to a predominance of matrix flow over bypass flow. This study suggests vertical movement of viruses varies significantly with soil type.

A change in the density of [(3)H]flumazenil, but not [(3)H]muscimol binding, in Brodmann's Area 9 from subjects with bipolar disorder

BACKGROUND

This study examines the hypothesis that there are changes in cortical serotonergic, GABAergic and glutamatergic systems in bipolar disorder and schizophrenia.

METHODS

In situ radioligand binding and autoradiography were used to measure neurochemical markers in Brodmann's Area (BA) 9 from control subjects and subjects with bipolar disorder or schizophrenia (n=8 per group).

RESULTS

Compared to tissue from schizophrenic (mean+/-S.E.M, 385+/-44 fmol/mg ETE) and control (383+/-44 fmol/mg ETE) subjects, there was an increase in the density of [(3)H]flumazenil binding to the benzodiazepine binding site on the GABA(A) receptor in subjects with bipolar disorder (451+/-17 fmol/mg ETE; P<0.05). There was no difference in the density of [(3)H]muscimol binding to the GABA(A) receptor or in the density of the serotonin(1A) receptor, serotonin(2A) receptor, ionotropic glutamate receptors or the serotonin transporter between the three cohorts. There was an age-related decrease in NMDA receptor density in control subjects that was absent in schizophrenia and bipolar disorder. An age-related increase in [(3)H]flumazenil binding in schizophrenia was absent in control and bipolar disorder subjects.

LIMITATIONS

This study involved a relatively small number of individuals.

CONCLUSIONS

An increase in the gamma2-receptor sub-unit in the GABA(A) receptor has been shown to increase benzodiazepine but not [(3)H]muscimol binding, this is the mismatch in binding we have shown in BA 9 from subjects with bipolar disorder. Thus, a change in the assembly of receptor subunits into GABA(A) receptors may be involved in the neuropathology of bipolar disorder. There may also be differences in age-related changes in cortical receptor density between bipolar disorder and schizophrenia.

Cpc2, a fission yeast homologue of mammalian RACK1 protein, interacts with Ran1 (Pat1) kinase To regulate cell cycle progression and meiotic development

The Schizosaccharomyces pombe ran1/pat1 gene regulates the transition between mitosis and meiosis. Inactivation of Ran1 (Pat1) kinase is necessary and sufficient for cells to exit the cell cycle and undergo meiosis. The yeast two-hybrid interaction trap was used to identify protein partners for Ran1/Pat1. Here we report the identification of one of these, Cpc2. Cpc2 encodes a homologue of RACK1, a WD protein with homology to the beta subunit of heterotrimeric G proteins. RACK1 is a highly conserved protein, although its function remains undefined. In mammalian cells, RACK1 physically associates with some signal transduction proteins, including Src and protein kinase C. Fission yeast cells containing a cpc2 null allele are viable but cell cycle delayed. cpc2Delta cells fail to accumulate in G(1) when starved of nitrogen. This leads to defects in conjugation and meiosis. Copurification studies show that although Cpc2 and Ran1 (Pat1) physically associate, Cpc2 does not alter Ran1 (Pat1) kinase activity in vitro. Using a Ran1 (Pat1) fusion to green fluorescent protein, we show that localization of the kinase is impaired in cpc2Delta cells. Thus, in parallel with the proposed role of RACK1 in mammalian cells, fission yeast cpc2 may function as an anchoring protein for Ran1 (Pat1) kinase. All defects associated with loss of cpc2 are reversed in cells expressing mammalian RACK1, demonstrating that the fission yeast and mammalian gene products are indeed functional homologues.

Quantifying the sustainability of grazed pastures on the Northern Tablelands of New South Wales

An experiment was conducted to examine the effect of deep-rooted perennial grasses on the water and nitrogen economy of 3 mature pasture communities with different botanical compositions but the same fertiliser history. One pasture was dominated by volunteer naturalised pasture grasses (Eleusine tristachya and Danthonia spp.) (termed ‘degraded’), another was phalaris (Phalaris aquatica) dominant (phalaris), and a third was dominated by phalaris into which white clover (Trifolium repens) had been recently sown (phalaris–white clover). Two replicates of each pasture type were grazed continuously over 4 years with young weaner sheep changed each year. Measurements of hydrology, nutrient cycling, botanical composition and animal production were made in order to quantify the sustainability characteristics of each of the pasture types. Data are summarised as absolute measures at various points in time and also as trends over time. The ranking of standardised treatment measures was then summed to provide an index of sustainability with or without a weighting assumed to be representative of the relative importance of various layers of sustainability viewed from the perspective of a hypothetical ‘typical’ grazier. The results show that the phalaris–white clover treatment was substantially more sustainable, in both ecological and economic terms, than either of the other treatments. The unweighted index for the phalaris–white clover pasture was 3.61 compared to 2.08 and 1.98 for the phalaris and ‘degraded’ pastures, respectively.

Prolonged xenograft survival of islets infected with small doses of adenovirus expressing CTLA4Ig

BACKGROUND

Systemic administration of the inhibitor of costimulation, CTLA4Ig, has been shown to prolong islet graft survival. The purpose of this study was to compare local and systemic expression of murine CTLA4Ig in transplants of rat islets into mice.

METHODS

Murine CTLA4Ig was made by joining two polymerase chain reaction products, the extracellular portion of CTLA4 and the Fc portion of IgG2a. Recombinant adenovirus expressing CTLA4Ig (AdCTLA4Ig) was generated using the strategy of Cre-lox recombination. Isolated rat islets infected with AdCTLA4Ig at multiplicities of infection (MOIs) ranging from 0.1 to 10 were transplanted into streptozocin diabetic male B6AF1 mice. Control islets were mock infected or infected with AdLacZ or AdsIg, a recombinant adenovirus expressing only the Fc portion of IgG2a. Also, AdCTLA4Ig and control viruses were injected intramuscularly into mouse transplant recipients at the time of islet transplantation to provide CTLA4Ig systemically.

RESULTS

Control islets transplanted into diabetic mice were rejected in 13-17 days. Islets infected with AdCTLA4Ig had dose-dependent prolongation of graft survival. Prolonged survival was even found with very low MOIs of 0.1 and 0.5, with survivals of 24+/-4.2 and 25+/-2.2 days, respectively. Survival with an MOI of 10 was 39+/-8.7 days. With intramuscular injection, no prolongation was found at the lowest relative MOIs of 0.2 and 1, but there was dose-dependent prolongation of graft survival with larger doses. At the highest relative MOI of 400, survival was prolonged to 58+/-10 days.

CONCLUSIONS

Rat islets infected with AdCTLA4Ig transplanted into mice had prolonged graft survival. Prolonged survival with MOIs as low as 0.1 and 0.5 indicates that only a minority of islet cells need to express CTLA4Ig to exert an effect. Moreover, the results suggest that the improved islet graft survival is due to a local influence of CTLA4Ig.

Establishing a method of vector contamination identification in database sequences

MOTIVATION

The nucleotide sequence databases are invaluable tools both for the private and the academic research communities, from the retrieval of sequences to homology searching. Several issues related to data quality, such as the existence of sequencing artifacts and errors, are facing the databases. We investigated a major source of these errors, i.e. the presence of vector-contaminated sequences.

RESULTS

Using a panel of 180 vector polylinker sequences, we found 0.36% or 3029 vector-matching sequences in GenBank Release 95-96, with an average vector-matching length of 72 nucleotides. The number of vector-contaminated sequences has been growing with the database; however, the percent contamination has remained approximately constant at an average of 0.28% from 1982 to 1996.

AVAILABILITY

Access to the database of vector polylinker sequences via sequence similarity searching is available at http://seqsim.ncgr.org/vector/

CONTACT

gas@molinfo.com

Characterization of functional regions in the Schizosaccharomyces pombe mei3 developmental activator

The Schizosaccharomyces pombe mei3(+) gene is expressed only in diploid cells undergoing meiosis. Ectopic expression of mei3(+) in haploid cells causes meiotic catastrophe. Mei3 is an inhibitor of Ran1/Pat1 kinase and contains a nine-amino-acid motif, Mei3-RKDIII, that resembles two regions in the Ste11 substrate for Ran1/Pat1. Substitution of serine for Arg-81 within Mei3-RKDIII transforms the inhibitor into a substrate for Ran1/Pat1. Thus, it is likely that Mei3-RKDIII defines a pseudosubstrate sequence. In this study, we constructed a series of mei3 deletion mutations and assayed each for activity. This analysis indicates that the carboxy-terminal domain of Mei3 is sufficient for function in vivo. Alanine-scanning mutagenesis identifies critical residues within the inhibitory domain. Two mutations, SM1 and SM8, fail to cause meiotic catastrophe. The SM1 mutation contains alterations of amino acid residues in Mei3-RKDIII. Recombinant SM1 protein exhibits reduced ability to inhibit Ran1/Pat1 kinase in vitro and interacts inefficiently with the kinase in a two-hybrid assay. The SM8 protein binds to Ran1/Pat1 in a two-hybrid assay but fails to inhibit Ran1/Pat1 substrate phosphorylation in vitro. These findings provide evidence that Mei3-RKDIII defines a Ran1/Pat1-binding site that is necessary but not sufficient for inhibition of the kinase. Using fusions to green fluorescent protein, the cellular localization of Ran1 and Mei3 was examined in living cells. Ran1 is concentrated in the nucleus. Mei3 is also enriched in the nucleus and, consistent with the genetic and biochemical results, the inhibitory domain of Mei3 is sufficient for nuclear localization.